<!Dcctype html>
<html > 
<head> 
<title>css布局案例实验页面-www.DIV CSS5.com.cn</title> 
<style>
#header,#centers,#footer{width:100%;margin:0auto;  
 
clear:both;font-size:18px;line-height:68px;font-weight:bold;}  
#header{height:68px;border:1pxsolid#CCCCCC;}  
#centers{padding:8px0;}  
#footer{border-top:1pxsolid#CCCCCC;background:#F2F2F2;}  
 
#centers.c_left{float:left;width:230px;border:1pxsolid#00CC66;  
 
background:#F7F7F7;margin-right:5px;}  
#centers.c_right{float:left;width:500px;border:1pxsolid#00CC66;background:#F7F7F7} 
</style>
</head>  
<body> 
<div id="header">我是头部（上）</div> 
<div id="centers"> 
<div class="c_left">我是中的左</div> 
<div class="c_right">我是中的右</div> 
<div class="clear"> </div> 
</div> 
<div id="footer">我是底部（下）</div> 
</body> 
</html> 